Lift-indicator eor elying-machines



A. s. REYNOLDS.

LIFT INDICATOR FOR FLYING MACHINES.

APPLICATION nun mm. 14. 1912.

1,387,5 1 4. ted Aug 16, 1921.

2 SHEETS-SHEET I.

Inventor A. s. REYNOLDS.

LIFT- INDICATOR FOR FLYING MACHINES.

APPLICATION FILED MAR. 14. I911.

1 ,5 1 4;, Patented Aug. 16, 1921.

, P- 2 SHEETS-SHEET 2- Q 1 x2, W

Inventor Atlor ya.

ANITA S. REYNOLDS, OF GREENWICH, CONNECTICUT.

LIFT-INDICATOR FOR FLYIN G-IVLACHIN ES.

Specification of Letters Patent.

Patented Aug. 16', 1921.

Application filed March 14, 1917. Serial No. 154,853.

To all whom it may concern Be it known that I, ANITA S. REYNOLDS, acitizen of the United States, and a resident of the town of Greenwich,county of Fairfield, and State of Connecticut, haveinvented a certainnew and useful Lift-Indicator for Flying-Machines, of which thefollowing is a specification.

My invention relates to flying machines of the heavier-than-air type inwhich the weight is sustained in the air by the reactions resulting whenone or more aerofoils are moved through the air edgewise at a suitableangle of incidence. This movement through the air causes a totalreaction on the aerofoils resultin in both positive and negativepressures being exerted on the lower and upper faces respectively.Posltive pressure being a compressive action on the under face of theaerofoil and negative pressure being a partial vacuum over the upperface. It is the resultant upward components of these reactions on theaerofoils which cause the machine to be sustained in the air. Themagnitude of this sustaining force is dependent on two generalconditions, 11. e. the angle of incidence of the aerofoils and the speedof the device.

The object of my invention is to provide means whereby an aviator willbe informed as to the sustaining force acting on the aerofoils at alltimes during flight and that such sustaining force is not dropping belowa certain minimum value known as the stalling point, that is, that valueat which the machine will fail to be sustained in the air.

A further object is to inform the aviator that certain maximum valuesare not exceeded when suddenly righting the machine in vol laning ordiving.

A urther object is to keep the aviator advised that he is operating themachine at such an angle as to secure the most efficient pressure on theaerofoils.

A still further object is to produce a device which will be simple andcheap in construction, effective in operation and not likely to get outof order.

These and further objects will more fully appear in the followingspecification and accompanying drawings considered'together orseparately.

I have illustrated one embodiment of my invention in the accompanyingdrawings in which like parts in all of the several figures are indicatedby similar reference characters and in which,

F gure 1 is a side elevation, partly in sectlon, of my invention, thesame being shown 1n connection with a visual indicator.

F g. 2 s a bottom plan view of the device.

F g. 3 1s a sectional view of a modification.

Ijlg. 4 1s a side elevation of a portion of a b1plane embodying myinvention, and

Fig. 5 1s a diagrammatic view of the devlce for automaticallystabilizing an airplane.

In carrying out my invention I employ a flexible diaphragm 1, preferablycorrugated, which is carried on an annular frame 2 and secured by itsedge to the annulus by means of a ring 3 which is fastened to the frameby means of screws 4 which pass through the edge of the diaphragm.

The frame 2 is secured in an aerofoil in such a manner that the upperface of the diaphragm is exposed to air currents on top of the aerofoilwhile its lower face is exposed to air currents on the bottom of theaerofoil.

A bracket 5 is carried by the ring 3. Pivoted to lugs 6 on the bracketis a bell crank lever '7. One arm of the bell crank is pivoted to a post8 which is rigidly secured to the center of the diaphragm 1. The otherarm of the bell crank 7 carries a pin 9 which en gages a slot in a lever10 pivoted in lugs 11 on the bracket. Carried on the pivot of the lever10 and insulated therefrom is,a contact finger 12.

The end of the bell crank lever 7 which engages the post 8 is normallyheld in contact with an adjusting screw 13 which is carried by an arm 14projecting from the bracket 5. A look nut 15 is provided for securingthe screw 13 in position. A spring 16 is secured to the bell crank 7 atone end while its opposite end is attached to a tensioning screw 17. Thescrew 17 is mounted in the bracket 5 and is provided with a lock nut 18.g

The free end of the finger is adapted to engage anyone of a series ofcontacts 19 carried 011 a standard projecting from the lower face of thering One pole of a source of current 20 is at tached to the finger 12and each of the contacts 19 is connected to an incandescent lamp 21carried in the fuselage of the machine at a point within the vision ofthe aviator.

The other side of each lamp is connected to a common return wire 22, inwhich is a switch 23, to the source of current.

Instead of the lamps 21 any other form of indicator may be employed.

In Fig. 3 I show two diaphragms 1 on or near the top surface of theaerofoil and 1 on or near the lower surface thereof. The diaphragms areconnected by a strut 2a the center of which is engaged by one arm of abell crank 7 the other arm of' which engages and operates a contactfinger which functions in the same manneras does the. finger 12 in Figs.1 and 2. By this construction airpockets 011 one side or the other of asingle diaphragm will be avoided. A perforation 25 in the upperdiaphragm 1 will serve to prevent a difference in altitude ortemperature from changing the relative positions of the diaphragms.

In multiplane machines it may be desirable to place one or moreinstruments in each aerofoil and in Fig. 4 I have shown a biplane withan instrument in each wing. It will be.understoo'd that more than oneinstrument in each wing may be employed if necessary or desirable.

As the angle of incidence depends upon the speed and weight of themachine it is obvious that at a given speed the lighter the machine theflatter, or more nearly the horizontal the angle of incidence, is, andthe most efiicient pressure will be different from that of a heaviermachine. During flight as the machine becomes lighter by reason of fuelconsumption or from any other reason the angle of incidence may beflattened and the minimum sustaining force will be lowered.

In Fig. 4 is shown means for indicating variations in the lift of themachine due to the consumption of fuel. A fuel tank 26 is shown indotted ilines. This tank may be located at any desired point and isillustrated as being withinthe fuselage 2?. The tank is provided with afloat 28 which is coupled to a pointer 29 which will indicate on the rowof lamps or other indicating device the position in which the diaphragm1 I should be when the most eiiicient operating condition of theairplane is reached as the load varies.

In Fig. 5 I have shown an arrangement in which the indicating device maybe employed for automatically stabilizing for pitchin In the figure isshown, diagrammatically, a: diaphragm 1, as before and a calibrated bellcrank 30. reversible motor 31 is mounted on trunnions 32 within thefuselage 27 and said motor has secured thereto an arm 33 which ezitendsover a counter'shaftfi on which are mounted the control levers. A pulley35 on the countershaft is connected by cables with a tail flap orelevator 36. The arm 33' passes over the countershaft and is curved on aradius struck from the center of the shaft. A

lever 37 is pivoted on the shaft and is provided with a sliding rod 38which is normally pressed downward by a spring A crank 40 is pivoted onthe lever and one arm thereof engages the upper end of the rod. A hook41:1 carried by the lower end of the rod 38 engages the under side ofthe curved portion of the arm 82 Carried on the countershaft is a wormwheel segment which is engaged by a worm as on the metor shaft.

The motor 31 is connected through a reversing box 1a with lead wires 15which connect with contacts 16 adapted to be engaged by a centralcontact 4-7 as the bell crank 30 is moved up or down by the airpressure. A source of current L8 is connected in series with thereversing box 4A and with the central contact I? by means of a lead wire19.

The operation of the device shown in Figs. 1, 2, 3 and 4 is as followslVhen the airplane is at rest the air pressure on opposite sides of thediaphragm 1 will be equal and it will therefore assume a centralposition. As the airplane is set in motion and gradually gains speed theair pressure on the bottom of the aerofoil will increase and decrease onthe upper face thereof. This will cause a consequent move ment of thediaphragm upward and by properly calibrating the spring 16 the devicemay be made to weigh the force tending to maintain the airplane in theair at all times.

. If with a given speed of the machine the indicator shows that thepressure is not sufficient to support it at the angle of incidence atwhich it is flying, the operator will swing the tail flap upward. Thiswill increase the angle of incidence above the horizontal until theindicator denotes that there is sutlicient pressure under the aerofoilto support the machine. The tail plane will now be lowered until thecraft flies on an even keel but with the increased angle of incidence.

In volplaning, when it is desired to right the machine the aviator byobserving the in dicator will be able to see that certain maximum valuesare not exceeded and that the machine is not strained beyond its safemechanical limits.

In the form of the device shown in Fig. 5 when the pressure on theunderside of the diaphragm decreases the center contact 17 will engagethe contact 46 and the motor will operate to raise the tail flap andpoint the machine upward. When the pressure on the bottom of thediaphragm increases the contact 17 will engage the contact 16, the motorwill be reversed and the tail flap will be lowered.

When it is desired to disconnect the automatic stabilizing devicethe'crank arm 40 is moved toward the lever 87. This will raise the hook41 and with it the arm 33 to tilt the motor on the trunnions anddisengage the worm from the worm wheel segment. The machine may now bemanually stabilized by the usual means.

The position of the diaphragm in the aerofoil may vary in differenttypes of machines but it preferably is so situated that it is free fromthe direct influences of the propeller orpropellers and near the centerof support of the airplane.

In accordance with the provisions of the patent statutes I havedescribed the principle of my invention, together with the apparatuswhich I now consider to represent the best embodiment thereof, but Idesire to have it understood that the apparatus shown is merelyillustrative, and that the invention may be carried out in other ways.

Having thus described my invention what I now claim as new and desire tosecure by Letters Patent, is:

1. An airplane comprising a supporting surface, propellin means, areceptacle adapted to carry el, a diaphragm in the supporting surface,an indicator actuated by the diaphragm for denoting the value of thelift on the supporting surface, and means actuated by variations in theload as the fuel is consumed forindicating the minimum value of the liftnecessary to sustain the airplane in the air.

2. 'An airplane comprising a plurality of supporting surfaces,propelllng means, a receptacle adapted to carry fuel, a diaphragm ineach supporting surface, an indicator actuated by the diaphragm fordenoting the value of the lift of the supporting surfaces, and meansactuated by variations in the load as the fuel is consumed forindicating the minimum value of the lift necessary to sustain theairplane in the air.

3. A device of the character described comprising an aerofoil, adiaphragm in the top camber, an axially alined diaphragm in the bottomcamber, said diaphragms being connected together at their centers, alever engaging the connection, and means actuated by the lever forindicating the air reactions above and below the aerofoil.

4. An aerofoil, a diaphragm in the top camber thereof, a diaphragm inthe bottom camber, a connection between the diaphragms, whereby saiddiaphragms may be deflected in unison by differences in air pressureabove and below said aerofoil, means for counterbalancing thedeflection, and means for indicating and recording the defiections ofthe diaphragms, said diaphragms being so situated relatively to the topand bottom cambers as to offer a minimum resistance to the passage ofthe aerofoil through the air.

This specification signed and witnessed this 12th day of March, 1917.

ANITA S. REYNOLDS.

Witnesses:

NIEL MORROW LODD, ETHEL H. TILSON.

